This week’s meeting of senior officials from the five original nuclear weapon states (the United States, Russia, the United Kingdom, France, and China) in Paris for the second meeting on nuclear weapons policy issues is a potentially important step toward multilateralizing the nuclear disarmament enterprise.

Their joint press statement (full text below) released today by the so-called “P5,”reaffirms the importance of the 64-point Action Plan approved at the 2010 nuclear Nonproliferation Treaty (NPT) Review Conference and specifically Action 5, which outlines further steps that are necessary to reduce the number and role of the world’s 20,000 remaining nuclear weapons and increase transparency regarding those stockpiles.

Many of the specific items called for in Action 5 still require leadership by the United States and Russia. Both countries still need to lead on deeper nuclear reductions, which do not require agreement on a new treaty in the near term to do so. New START puts the two nations back on the path to verifiable reductions of strategic deployed warheads and their associated delivery systems, but it leaves both countries with far more weapons than is necessary to fulfill the fundamental purpose of these weapons: deterring a nuclear attack by another state.

Russia is already below New START ceiling of 1,550 deployed strategic warheads and should continue the ongoing process of retiring old strategic systems. Washington should incentivize and reciprocate this process by furthering its own reductions, recognizing that its existing nuclear missions can still be met with numbers well below New START.

Given that no other country deploys more than 300 strategic warheads and given that China possesses 40 to 50 warheads on intercontinental-range missiles, the United States and Russia could reduce their overall nuclear stockpiles substantially—to 1,000 warheads—while retaining sufficient firepower to deter nuclear attack by any current or potential adversary.

As the 2007 Arms Control Association report “What Are Nuclear Weapons For?” suggests, the United States could move to a smaller force of 500 deployed and 500 nondeployed strategic warheads on a smaller, mainly submarine-based triad within the next few years.

In order to help open the way for reductions of nuclear weapons stockpiles “of all types” and “regardless of their location,” NATO should acknowledge, as part of its Defense and Deterrence Posture Review due to be completed next year, that the 180 or so forward-deployed U.S. tactical nuclear weapons are not necessary for deterrence purposes and indicate its readiness to withdraw those weapons if Russia takes reciprocal measures.

Other nuclear weapon states have important roles to play too. Today’s press statement said that the P5 discussed issues related to transparency, “including nuclear doctrine and capabilities,” as well as verification. That dialogue should continue with a view to providing greater information regarding P5 nuclear weapon stockpiles and reducing the role of nuclear weapons in their security policies. The discussions to be held later this year in London on verification should build on the disarmament verification work pursued by the United Kingdom and Norway, with additional P5 states carrying out similar research.

The P5 statement calls for the “swift entry into force” of the Comprehensive Test Ban Treaty (CTBT) and its “universalization.” Reiterating the words in Article I of the CTBT that prohibit any and all nuclear test explosions and establish a “zero-yield” test ban, the P5 “called upon all States to uphold the moratorium on nuclear weapons-test explosions or any other nuclear explosion, and to refrain from acts that would defeat the object and purpose of the treaty pending its entry into force.”

It is important that the P5 governments and others back up their words with action.

On March 29, National Security Advisor Tom Donilon reiterated the Obama administration’s support for prompt U.S. ratification and entry into force, and Under Secretary of State Ellen Tauscher said on May 10 that the administration has begun to explain the administration’s case to the Senate. It will take some time to lay the groundwork for ratification, but a sustained effort can achieve Senate approval before the 2015 conference.

While France, Russia and the United Kingdom have signed and ratified the CTBT, Beijing must also act. The Chinese government has said for many years that it had begun the ratification process and it should also seek to conclude that process without further delay.

The dialogue initiated by the P5 is an important step and should continue so that the five countries can offer a positive report on progress at the 2014 NPT PrepCom, paving the way for strengthening the treaty the following year.

They reaffirmed their unconditional support for the NPT, which remains the cornerstone of the nuclear non-proliferation regime and the essential foundation for the pursuit of nuclear disarmament, and for the peaceful uses of nuclear energy. They also reaffirmed the recommendations set out in the balanced Action Plan agreed in the Final Document of the 2010 NPT Review Conference, and called on all States Parties to the NPT to work together to advance its implementation.

They met with the determination to work together in pursuit of their shared goal of nuclear disarmament under article VI of the NPT, including engagement on the steps outlined in Action 5, as well as reporting and other efforts called for in the 2010 Review Conference Action Plan. They called on all States, both States Parties and Non Parties, to contribute to this nuclear disarmament objective, including by ensuring that the international nuclear non-proliferation regime remains robust and reliable.

The P5 continued their previous discussions on the issues of transparency and mutual confidence, including nuclear doctrine and capabilities, and of verification, recognizing such measures are important for establishing a firm foundation for further disarmament efforts. In order to increase efficiency of P5 nuclear consultation, they approved to continue working on an agreed glossary of definitions for key nuclear terms and established a dedicated working group.

The P5 discussed the particular political and technical challenges associated with verification in achieving further progress towards disarmament and ensuring non-proliferation. They shared information on their respective bilateral and multilateral experiences in verification. They will continue their discussion of this issue later this year at an expert-level meeting in London.

As a follow-up to the 2010 NPT RevCon discussions, the P5 shared their views on how to respond to notifications of withdrawal from the Treaty, while recognising the provisions of article X. They also stressed the need for strengthening IAEA safeguards, including through promoting the adoption of the Additional Protocol and the reinforcement of IAEA’s resources and capabilities for deterring and detecting non-compliance.

The P5 States recalled their commitment to promote and ensure the swift entry into force of the CTBT and its universalization. They called upon all States to uphold the moratorium on nuclear weapons-test explosions or any other nuclear explosion, and to refrain from acts that would defeat the object and purpose of the treaty pending its entry into force. They reiterated their support for immediate commencement of negotiations at the Conference on Disarmament (CD) on fissile material cut-off treaty (FMCT) banning the production of fissile material for nuclear weapons or other nuclear explosive devices, including verification provisions. In order to sustain the potential of negotiations in the CD, the P5 will, prior to the next UNGA, renew their efforts with other relevant partners to promote such negotiations.

The P5 welcomed the steps taken by the US, Russia and UK towards holding a Conference on a Middle East WMD Free Zone (MEWMDFZ) in 2012.

The P5 will follow on their discussions and hold a third P5 Conference in the context of the next NPT Preparatory Committee.